DRAFT TOTAL MAXIMUM DAILY LOAD FOR FECAL COLIFORM
ON SIX-MILE, CIENEGUILLA AND MORENO CREEKS
CANADIAN RIVER BASIN (CIMARRON)
Summary Table
New Mexico Standards Segment /Canadian River Basin, 2306
Waterbody Identifier / Moreno Creek from the inflow to Eagle Nest Lake to the headwaters (CR2-30000)Total Waterbody Mileage: 14.4 miles
Six-Mile Creek the inflow to Eagle Nest Lake to the headwaters (CR2-40000)
Total Waterbody Mileage: 6.6 miles
Cieneguilla Creek from the inflow to Eagle Nest Lake to the headwaters (CR2-50000)
Total Waterbody Mileage: 13.6 miles
Parameters of Concern / Fecal coliformUses Affected / High Quality Cold Water Fishery
State Priority / 4
Threatened or Endangered Species / None
Geographic Location / Canadian River Basin, Cimarron River Sub-Basin
Scope/size of watershed / Six-Mile Creek 10.5 mi2
Moreno Creek 73.8 mi2
Cieneguilla Creek 56 mi2
Land type / Southern Rockies Ecoregion
Land use/cover
/ Forests, 89%; Rangeland 38%; Agriculture 9%; Urban, 1.4%; Water 0.6%
Identified Sources / Rangeland Grazing, Animal Holding/Management Areas, Wildlife Impacts
Watershed Ownership / 89% Private, 9% Forest Service, 2% State.
TMDL Load Allocations:
WLA + LA + MOS = TMDL
Cieneguilla Creek
Six-Mile Creek
Moreno Creek / 0 + 6.35x1010fcu/day + 0 = 6.35x1010fcu/day
0 + 3.16x109fcu/day+ 0 = 3.16x109fcu/day
0 + 5.01x109fcu/day+ 0 = 5.01x109fcu/day
Table of Contents
List of Abbreviations......
Executive Summary......
Background Information......
Figure 1 Cimarron Watershed Land Use/Cover Map...... 2
Figure 2 Cimarron Watershed Land Ownership …………………………….3
Identification of Sources...... 4
Point Sources......
Nonpoint Sources......
TMDL Load Calculations......
Calculations of Stream Loading Capacity......
Figure 3aFecal Coliform Loading Curve for Cieneguilla Creek...... 6
Figure 3bFecal Coliform Loading Curve for Six-Mile Creek……………....7
Figure 3cFecal Coliform Loading Curve for Moreno Creek...... 7
Current Load Evaluations……………………………………………….8
Waste Load Allocation......
Load allocation......
Seasonal Variability......
Future Growth......
Margin of Safety......
TMDL Specific Monitoring......
Implementation Plan......
Management Measures......
Timeline......
Assurances......
Milestones
Monitoring plan......
Public Participation......
Figure 4Public Participation Flowchart……………………………………15
Apendices
Appendix A Public Comments
References Cited
List of Abbreviations
4Q3Minimum average four consecutive day flow which occurs with a frequency of once in three years
BMPBest Management Practice
BOD Biochemical Oxygen Demand
CBODCarbonaceous Biochemical Oxygen Demand
CFSCubic Feet per Second
CFUColony Forming Unit
CWAClean Water Act
CWAPClean Water Action Plan
CWFCold Water Fishery
DMRDischarge Monitoring Report
EPAEnvironmental Protection Agency
HQCWFHigh Quality Cold Water Fishery
LALoad Allocation
MGDMillion Gallons per Day
mg/LMilligrams per Liter
MOSMargin of Safety
MULTI-SMPMultiple Discharge Version of the Simplified Method Program
MQLMinimum Quantification Level
NMEDNew Mexico Environment Department
NPDESNational Pollution Discharge Elimination System
NPSNonpoint Sources
NTUNephelometric Turbidity Units
SWQBSurface Water Quality Bureau
TA Total Ammonia
TMDLTotal Maximum Daily Load
TPTotal Phosphorous
TRCTotal Residual Chlorine
TSSTotal Suspended Solids
UWAUnified Watershed Assessment
WLAWaste Load Allocation
WQLSWater Quality Limited Segment
WQCCNew Mexico Water Quality Control Commission
WQSWater Quality Standards
WWTPWaste Water Treatment Plant
EXECUTIVE SUMMARY
Section 303(d) of the Federal Clean Water Act requires states to develop TMDL management plans for water bodies determined to be water quality limited. A TMDL documents the amount of a pollutant a water body can assimilate without violating a state’s water quality standards. It also allocates that load capacity to known point sources and nonpoint sources. TMDLs are defined in 40 CFR Part 130 as the sum of the individual Waste Load Allocations (WLA) for point sources and Load Allocations (LA) for nonpoint sources, including a margin of safety and natural background conditions.
Cieneguilla, Moreno and Six-Mile Creeks flow from their headwaters to a terminal discharge into Eagle Nest Lake. The New Mexico 1998 303(d) report, “State of New Mexico 303(d) List for Assessed Stream and River Reaches,” lists this segment as being water quality limited for the following pollutants: stream bottom deposits, turbidity, and fecal coliform. Sampling results from intensive surveys conducted in 1998 support these listings. This Total Maximum Daily Load (TMDL) document addresses only the fecal coliform listing. TMDL documents addressing turbidity and stream bottom deposits were addressed in the SWQB document Total Maximum Daily Load for Turbidity, Stream Bottom Deposits, and Total Phosphorous in the Canadian River Basin (Cimarron) (1999).
New Mexico Standards for Interstate and Intrastate Streams (WQCC, 1995) (Standards) identify Cieneguilla, Six-Mile and Moreno Creeks as having an aquatic life use designation as high quality coldwater fishery. With other designated uses of domestic water supply, irrigation, livestock watering, wildlife habitat, municipal and industrial water supply, and secondary contact. These Standards specify specific constituent criteria levels to be maintained so that the water body can support these designated uses. TMDL targets specified in this document are based on these water quality standards criteria. TMDL numeric targets are calculated so as to provide protection of designated uses. Load capacities are estimated as a function of these water quality targets and the assimilative capacity of these streams. Load allocations presented in this TMDL are based on the load capacities developed using these targets. Targets, loading analyses, and load allocations are presented for fecal coliform. These load analyses show that the estimated load capacities are currently exceeded, and therefore require reductions.
A general implementation plan for activities to be established in the watershed is included in this document. The Surface Water Quality Bureau’s Point Source Regulation and Nonpoint Source Pollution Sections will further develop the details of this plan. Implementation of recommendations in this document will be done with full participation of all interested and affected parties. During implementation, additional water quality data will be generated. As a result targets will be re-examined and potentially revised; this document is considered to be an evolving management plan. In the event that new data indicate that the targets used in this analysis are not appropriate or if new standards are adopted, the load capacity will be adjusted accordingly.
1
Background Information
The Cimarron River Basin, a sub-basin of the Canadian River Basin, is located in northeastern New Mexico. Eagle Nest Reservoir formed with a concrete dam is located in the headwaters of this sub-basin and collects flows from Cieneguilla, Six-Mile and Moreno Creeks prior to discharge through a natural rock spillway. Six-Mile Creek from the inflow to Eagle Nest Lake to the headwaters has a watershed of 10.5 square miles, Moreno Creek watershed encompasses 73.8 square miles and Cieneguilla Creek watershed encompasses 56 square miles. The mean annual precipitation is 13.1 inches.
Six-Mile, Cieneguilla, and Moreno Creeks are listed on the 1998 303(d) list with fecal coliform (FC) as a pollutant of concern. FC bacteria are that portion of the coliform group that are present in the gut of warm-blooded animals. It is an indicator of the possible presence of other bacteria that may limit beneficial uses and present human health concerns. Primary sources of FC are from human wastes, the source of greatest concern, and from other warm-blooded animals including wild or domesticated animals.
Water quality standards for these watercourses are set forth in sections 1102, 2306 and 3101 of the New Mexico water quality standards (NMWQCC, 1991). Section 2306 defines the designated uses of these streams as including; domestic water supply, irrigation, high quality coldwater fishery, livestock and wildlife watering, municipal and industrial water supply, and secondary contact recreation. The most stringent FC criterion is set forth in the segment specific standard (Section 2306) which states, “The monthly geometric mean of fecal coliform bacteria shall not exceed 100/100 ml; no single sample shall exceed 200 (cfu)/100 ml. Section 1103.B of the standard document states that the monthly geometric mean shall be used in assessing attainment of standards when a minimum of five samples is collected in a 30-day period. For purposes of compliance with this standard a criterion of 200(cfu)/ 100 ml will be applied.
Surface water quality monitoring stations were used to characterize the water quality of the stream reaches. Stations were located to evaluate the impact of tributary streams and to establish background conditions (Figures 1 and 2). As a result of this monitoring effort, several exceedances of New Mexico water quality standards for FC were documented on these streams flowing into Eagle Nest Reservoir. In all cases the exceedances were observed during summer months.
Figure1.
Figure2.
Identification of Sources
Sampling for FC has been conducted by the SWQB during surveys in 1992-1993 and 1998-1999. When available flows are from the USGS gages located at the lower ends of each stream.
Data from these surveys is summarized in Table 1.
Table 1.Results of fecal coliform monitoring from 1993 through 1999
Date / CieneguillaCreek,
fcu/100ml1 / Cieneguilla Creek
flow, cfs / Sixmile
Creek
fcu/100ml / Sixmile
Creek
flow, cfs / Moreno
Creek
fcu/100ml / Moreno
Creek
flow, cfs
12/2/92 / 3/62/55/24 / -- / 19 / -- / 19 / --
1/6/93 / 3/1/3/10/11 / -- / 18 / -- / 9 / --
3/24/93 / 1/1/3/3/2 / -- / 2 / -- / 4 / --
5/5/93 / 1/4/2/40 / 87 / 22 / 23 / 1 / 41
7/20/93 / 600/210/180180/600 / 3.1 / 2500 / .91 / 400 / 2.1
9/9/93 / 360/80/60/
330/390 / 3.0 / 90 / 3.2 / 300 / 2.3
10/20/93 / 62/29/8/4/34 / -- / 25 / 1.9 / 107 / 2.0
5/14/98 / -- / -- / 720 / 6.1 / 220 / 7.2
7/30/98 / 110/9 / 1.8 / -- / -- / -- / --
10/8/98 / 12/14 / -- / 32 / -- / -- / --
2/8/99 / -- / -- / <10 / -- / 1 / --
3/15/99 / 14 / 5.4 / 2 / 2.1 / 14 / 1.7
4/19/99 / 7 / 6.8 / 1 / 1.3 / 1 / 2.3
6/1/99 / 77 / 21 / 200 / 3.9 / 86 / 20
7/6/99 / >1600 / 8.9 / >1600 / 1.3 / >1600 / 8
1 Multiple listings are values collected at different sites on the same day.
Point Sources
There are no known point sources discharging to these stream reaches.
Nonpoint Sources
Howell et. al. (1996) found that FC concentrations in underlying sediment increase when cattle (Bos taurus) have direct access to streams. Sherer et al. (1992) found that FCs survived longer in fine sediments rather than coarse sediments. Both of these streams are listed in the New Mexico 303(d) list as impacted due to fine sediments. In addition to direct input from grazing operations FC concentrations in such streams may be subject to elevated levels as a result of re-suspension of FC laden sediment. Temperature also plays a role in FC concentrations.
Howell et. al. (1996) observed that FC re-growth increases as water temperature increases.Natural sources of FC are also present in the form of other wildlife such as elk, deer, and any other warm blooded mammals. The primary land-use in these watersheds is grazing with almost 90% of the land being privately held. Cattle have full access to the stream for most of the full length of each stream. During winter periods cattle are removed from the watershed and moved to lower elevationsand are reintroduced during late spring and remain through early fall months. A seasonal pattern is present in the data presented in Table 1. As summer months approach, FC levels increase as: water temperatures increase, numbers of grazing stock increase, and summer rains contribute to re-suspension of FC laden sediments. Collectively in the three streams during the summer period late May through September 16/23 samples collected were above the criterion. Other seasonal values are well below criterion levels with 0/46 samples from non-summer months greater than the criterion.
TMDL Load Calculations
Calculations of Stream Loading Capacity
Given that fecal coliform standards are expressed as colonies per unit volume, using the criterion of 100-cfu/100 ml a target stream load can be calculated. The geometric mean criterion is utilized in these calculations because it is conservative. Also if the 200 cfu/100 ml were used as a target the geometric mean criterion of 100 fcu/100 ml may not be reached. This load is through application of the following conversion.
Equation 1
C as fcu/100 ml * 1000ml/1 L * 1 L/ 0.264 gallons * Q in gallons / day = Fu/day
Where:C = State water quality standard criterion, 100 FCU/100 ml
Q = defined stream flow in gallons
Point sources usually have a defined critical low receiving stream flow such as the 4Q3 at which the criterion must be met. For nonpoint sources it is important to recognize that there may be no single critical flow condition. The water quality criterion may be exceeded during low flow but it is equally likely that the criterion will be violated during wet weather events when the pollutant is washed off the land surface or re-suspended from contaminated sediments. To address this condition, and hopefully to increase understanding of the TMDL loaddetermination process, a FC loading curve has been generated. This line is developed using Equation 1, substituting the criterion, 100 fcu/100 ml, for FC concentration and varying flow. The attempt here is to show that while a TMDL may be expressed as a single point it can also be thought of as a continuum of points representing the criterion value and various flow values. This curve is not stream dependent but is dependent upon the designated stream criterion. Therefore, it may be applied to any stream with a like FC criterion. This curve represents the TMDL loading allocation for FC on the above listed streams.
This loading capacity line is shown in Figures 3a,b,c. For any flow value x, one can quickly determine the FC loading value. For ease in dealing with very large numbers generated from FC loading conversions the y-value, FC concentrations, is expressed as the log 10 transformation of the FC concentration. The line formed by this series of points may be thought of as a boundary. At any given flow the loading may be below the line, within the boundary, or above the line. FC load values falling above the line represent disproportionately high values relative to the standard. FC load values falling below the line represent low loads relative to the standard. For the three streams addressed in this document values above the line generally occur within a flow range centered around 2 cfs. This is representative of summer flow conditions. To develop load reductions one simply needs to determine the appropriate flow value (x-axis) and see where it intersects the load allocation line. For example on the Cieneguilla Creek plot (Figure 3a) there are two measured data points at a flow of approximately 3 cfs and a log 10 fcu value of about 10.3. Taking the inverse log of 10.3 we arrive at a concentration of 1.995 x 1010 fcu/day. Using the same chart the loading curve value for 3 cfs is about 9.8 FCU. Again, converting this value to a concentration yields 6.31 x 109 fcu/day. The load reduction for this value would be thedifference of these values or 1.36 x 1010 fcu/day. Similar values may be calculated using graphs 3b and 3c for Six-Mile and Moreno Creeks. Flow values used are flows at actual sample times and are considered to be representative of summertimeflow in these streams. These values are shown in Table 2.
Figure 3a. Fecal coliform loading curve for Cieneguilla Creek
Figure 3b. Fecal coliform loading curve for Six-Mile Creek
Figure 3c. Fecal coliform loading curve for Moreno Creek
Table 2. Loading Calculations
Stream / Flow, cfs / Concentration, fcu/day / TMDL Load, fcu/dayCieneguilla / 3.0 / 1.995x1010 / 6.35x1010
Six-Mile / 0.9 / 5.01x1010 / 3.16x109
Moreno / 2.0 / 1.58x1010 / 5.01x109
Current Load Evaluations
A traditional expression of the FC loading may be developed by setting one critical or representative flow and concentration, and calculating the load allocation using Equation 1. The difficulty with this approach is in the determination of the appropriate flow or concentration value to use. From Table 1 one can see that summer flow values are highly variable. For example, Cieneguilla Creek ranges from a low of 3.0cfs to a high of 21 cfs. Six-Mile and Moreno Creeks are equally variablemakingit difficult to establish a critical flow. FC levels in the streams have no definable pattern as well. On Cieneguilla Creek the FC concentration was 77 FC/100 ml at a flow of 21 cfs and >1600 FC/100 ml at 8.7 cfs. Selection of an appropriate flow for expressing the TMDL can be difficult. This document proposes an alternative solution to the traditional approach. Utilizing the charts developed in the previous section it is possible to quickly evaluate deviations, both in magnitude and frequency from the criterion. For example, from the Cieneguilla Creek curve, Figure 3a, it can be determined that four of seven points fall above the curve. From a similar evaluation of Figures 3b,c, for Six-Mile and Moreno Creeks it can be seen that both the frequency (5/9) and magnitude of exceedances are greater in Moreno Creek. A deviation from the criterion can be calculated for each individual excursion. These values may then be averaged to obtain a mean deviation from the standard. This value has more meaning in that it has been calculated using actual reductions at several points. Load reductions calculated in this manner, yield average load reduction values of 1.12x1010 fcu/day for Cieneguilla Creek, 3.5x1010 fcu/day for Six-Mile Creek, and 9.1x1010 fcu/day for Moreno Creek.
Waste Load Allocation (WLA)
There are no point sources of fecal coliform identified in these watersheds. The WLA will be set to zero.
Load Allocation (LA)
The full allocations for these watersheds are applied to the LA, no attempt is made to define a background level. There is no appropriate stream in this watershed that allows determination of least impacted conditions. NMED has not established background concentrations for FC values for broader regions.
Seasonal Variability
There is an identifiable seasonal trend associated with FC in these watersheds with the critical period for FC being generally late-May to mid-September. This TMDL has been developed along a continuum formed by the variation in flow and the water quality standard criterion. The criterion is applicable to all seasons. This presentation addresses all flow conditions observed on this segment without creating an artificial “critical” flow condition.
Future Growth
NMED does not allocate for future growth for TMDLs without point sources.
Margin of Safety (MOS)
TMDL regulations allow the use of implicit orexplicit expression of the MOS. When conservative assumptions are used to develop the model calculation the MOS can be implicit. TMDLs in this document have an implicit MOS. Significant conservative assumptions have been used in developing these loading limits. These include: